PROJECT SUMMARY The goal of this supplement award is to provide supplemental support for the sample processing and polypeptide vaccine (NSC 804336) manufacture for patients enrolled in NCI protocol #10146. This is a CTEP sponsored protocol with the primary objective to evaluate the clinical response to nab-paclitaxel + MEDI4736 (durvalumab) + neoantigen vaccine (Arm 1) vs. nab-paclitaxel + MEDI4736 (durvalumab) (Arm 2) in patients with metastatic triple negative breast cancer (TNBC). The primary endpoint is progression-free survival (PFS) which is defined as time from the initiation of Part B to progression or death. The secondary objective is to evaluate the safety of nab-paclitaxel + MEDI4736 (durvalumab) + neoantigen vaccine vs. nab-paclitaxel + MEDI4736 (durvalumab) in patients with metastatic TNBC. Safety will be assessed by clinical evaluation (CTCAE v. 5.0). Other secondary endpoints include clinical response (RECIST FOLQLFDO EHQHILW UDWH &5 35 RU 6' DW PRQWKV DQG RYHUDOO VXUYLYDO 26 Washington University will oversee the design, production and release of the investigational neoantigen vaccine agent (NSC 804336) to clinical sites for administration to patients enrolled in the NCI protocol #10146.